Clutches are well known in the art and are generally used to transmit force between two rotating shafts. One of the shafts is typically attached to a motor, sometimes referred to as the driving member, and the other shaft provides output power for work to be done, often referred to as the driven member. The clutch connects the two shafts across a slip joint so that they can be either engaged so that they spin at the same speed, or decoupled and disengaged so they spin at different speeds.
German Patent Publication DE102004054890 B3 is directed to a clutch that is adjusted by tightening a compression nut positioned outside of a spring on the threaded end of a rod that is connected at the other end to a pressure disk which is pressured to increase friction against a movable friction plate.
German Patent Publication DE19927847 C1 is directed to a slip clutch that is adjusted by tightening a compression nut positioned outside of a spring on one end of a threaded pull rod that is connected at the other end to a pressure disk which is pressured to increase friction between clutch discs.
U.S. Pat. No. 5,853,165 is directed to a clutch in which the preload of disks is provided by a nut acting on a helical spring and screwed onto a corresponding thread on a stub shaft that projects beyond the clutch disk and a second spring.
German Patent Publication DE4408578 A1 is directed to a slip clutch which can be adjusted without opening the casing. A shaft carries an external thread onto which a nut is screwed. A compression spring acts between the nut and a bearing such that the spring bias force on friction rings can be adjusted.
United Kingdom Patent Application GB2321504 A is directed to a slip clutch in which the amount of friction force is varied by rotation of an adjustment member on a threaded shaft portion.
U.S. Pat. No. 5,533,712 is directed to a slip clutch having an elastic member and an adjustment member.
DE19757500 is directed to a clutch with an adjustment mechanism comprising a compression spring in a cap having a threaded ring that is in threaded engagement with a threaded portion of a shaft.
U.S. Pat. No. 1,807,210 is directed to a friction coupling and generally discloses a key gear having a hub, follower ring, spring and cylindrical shell.
U.S. Pat. No. 2,953,911 is directed to a drive coupling and discloses a driven plate with radial grooves, hub, driving plate, pressure plate and clutch springs.
U.S. Pat. No. 7,591,357 is directed to a crank shaft torque modulator and discloses a driven hub, clutch spring, carrier disk, thrust washer, crank shaft pulley and mounting hub.